The present invention relates to a clamping device for attaching a tool holder to various kinds of machine tools including a lathe, a numerical controlled lathe and an automatic copying lathe, for example.
A conventional tool assembly 101 comprising a support body 102 and a plurality of tool holders 111 is depicted in FIG. 15. A clamping device for securing each tool holder 111 in a respective recess of the support body includes a wedge clamp 112, a plurality of fastening bolts 114, and a jack-up bolt 113. The fastening bolts extend through the wedge clamp and are fastened to the support body 102, so that the tool holder can be connected to the support body via interaction between respective wedge surfaces (not shown) of the clamp 112 and the support body, which interaction pushes the clamp 112 against the respective tool holder 111, thereby pushing the tool holder against an abutment surface of the support body. When the tool holder is to be removed from the clamping device, the jack-up bolt 113 is screwed against the support body after the plural clamping bolts 114 have been loosened, so that the wedge surface of the clamp is forcefully moved away from the wedge surface of the support body. That enables the tool holder to be adjusted or replaced.
Various kinds of devices for attachment/removal of the tool holder are well known. A device for holding a tool holder shank in a machine tool is disclosed in Japanese Unexamined Patent Publication No. 2000-190110 (corresponding to U.S. Pat. No. 5,415,006). The device releasably holds a holder shank of the tool holder to which a cutting insert is attached and a lock rod is provided on a base member. The attachment/removal structure between the holder shank and the lock rod is complicated and it is difficult to reduce the size of the device.
Japanese Unexamined Patent Publication No. 2001-300802 discloses a detachable securing mechanism of a cutting tool used in a comb-type tool rest of a machine tool such as a numerical controlled lathe. The mechanism is provided with a supporting member for supporting an arrangement of plural tools. The supporting member is attached the cutting tool to the comb-type tool rest of the machine tool by fastening a plurality of mounting bolts.
Disclosed in Japanese Patent Application No. 2003-207909 is a stopper disposed in a recess behind a tool holder in abutment therewith. When a fine adjustment of the tool holder is required, the tool holder is unclamped, and a screw provided on the stopper is advanced to displace the tool holder. The stopper does not aid in pressing the tool holder against abutment surfaces of the support body.
However, in the above conventional clamping devices for a tool holder, it takes a long time to attach/remove the tool holder because it is required that a plurality of clamping bolts be fastened or loosened in order to remove the clamp. Also, the tool holders may accidentally fall out of their recesses once they have been unclamped, e.g., due to gravity, depending on the orientation of the support body.